The program will only multi-pick boxes that have consecutive box numbers in the pattern, e.g. 37 and 36 can be picked together.
There are some other limitations as well:
space between the boxes can’t be too much (“box padding” defines the maximum space allowed)
box rotations in the pattern must be “compatible” (see the small arrows on the top of the boxes and “lock direction” button in Pallet Builder)
pick position must be within reach (picking multiple boxes may require the robot move further away above the conveyor)
drop position must be within reach (dropping multiple boxes may require the robot move further away from the base)
payload can’t exceed the maximum allowed weight (can be altered via rf_max_payload parameter)
the stop multi-pick flag is not set (see the small hand icon and “stop multiple pick” button in the Pallet Builder)
the number of “product sensors” must be configured (e.g. you’ll need 2 sensors to indicate there is enough room to drop 2 boxes on the conveyor, 3 sensors for 3 boxes, etc.) see under Installation / Pally / Input-Output